Package zeroecho.core.alg.common.agreement

Class KemMessageAgreementAdapter

java.lang.Object

zeroecho.core.alg.common.agreement.KemMessageAgreementAdapter

All Implemented Interfaces:

Closeable, AutoCloseable, AgreementContext, CryptoContext, MessageAgreementContext

public final class KemMessageAgreementAdapter
extends Object
implements MessageAgreementContext

Adapter: using a KEM as a message-based agreement primitive

KemMessageAgreementAdapter adapts a KemContext into a MessageAgreementContext, making KEMs usable in higher-level protocols that expect a two-party message agreement API.

Roles

• KemMessageAgreementAdapter.Role.INITIATOR - encapsulates to a peer’s public key, producing a ciphertext (peer message) and shared secret.
• KemMessageAgreementAdapter.Role.RESPONDER - receives a peer message (ciphertext), decapsulates with their private key, and derives the shared secret.

Lifecycle

1. Create via KemMessageAgreementAdapter.Builder with a bound KemContext.
2. Initiator calls getPeerMessage() to obtain ciphertext to transmit.
3. Responder calls setPeerMessage(byte[]) with received ciphertext.
4. Both parties call deriveSecret() to obtain the agreed secret.

Thread-safety

Instances are not thread-safe; synchronize externally if sharing across threads.

Since:

1.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	KemMessageAgreementAdapter.Builder	Builder for KemMessageAgreementAdapter.
static enum	KemMessageAgreementAdapter.Role	Role of the adapter: initiator or responder.

Method Summary

Modifier and Type	Method	Description
CryptoAlgorithm	algorithm()	Returns the underlying algorithm descriptor.
static KemMessageAgreementAdapter.Builder	builder()	Returns a new builder for constructing a KemMessageAgreementAdapter.
void	close()	Closes the underlying KEM context if it is closeable.
byte[]	deriveSecret()	Derives the shared secret from this exchange.
byte[]	getPeerMessage()	Returns the ciphertext produced by encapsulation.
Key	key()	Returns the key bound to the underlying KEM context.
void	setPeerMessage(byte[] message)	Stores the peer’s ciphertext for decapsulation.
void	setPeerPublic(PublicKey peer)	No-op for KEM-based contexts.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

builder

public static KemMessageAgreementAdapter.Builder builder()

Returns a new builder for constructing a KemMessageAgreementAdapter.

Returns:

builder instance

setPeerMessage

public void setPeerMessage(byte[] message)

Stores the peer’s ciphertext for decapsulation.

Specified by:

setPeerMessage in interface MessageAgreementContext

Parameters:

message - ciphertext received from initiator

Throws:

IllegalStateException - if called in initiator mode

getPeerMessage

public byte[] getPeerMessage()

Returns the ciphertext produced by encapsulation.

Specified by:

getPeerMessage in interface MessageAgreementContext

Returns:

defensive copy of ciphertext to send

Throws:

IllegalStateException - if called in responder mode

setPeerPublic

public void setPeerPublic(PublicKey peer)

No-op for KEM-based contexts.

Unlike Diffie–Hellman, KEMs are already bound to the correct key at construction. This method exists for interface symmetry.

Specified by:

setPeerPublic in interface AgreementContext

Parameters:

peer - ignored

deriveSecret

public byte[] deriveSecret()

Derives the shared secret from this exchange.

Specified by:

deriveSecret in interface AgreementContext

Returns:

defensive copy of the derived secret

Throws:

UncheckedIOException - if encapsulation/decapsulation fails

algorithm

public CryptoAlgorithm algorithm()

Returns the underlying algorithm descriptor.

Specified by:

algorithm in interface CryptoContext

Returns:

algorithm bound to this adapter

key

public Key key()

Returns the key bound to the underlying KEM context.

Specified by:

key in interface CryptoContext

Returns:

encapsulation (public) or decapsulation (private) key

close

public void close()
           throws IOException

Closes the underlying KEM context if it is closeable.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface CryptoContext

Throws:

IOException - if the wrapped context fails to close